The present invention relates to oil well pumping and like applications and is particularly characterized by the carrying out of such pumping in a noiseless manner with high efficiency in utilization of energy and reduced vulnerability to breakage.
Some 85% of oil wells use driven motor pumps to raise oil from deep sub-surface pools to ground level and of these some 85% are sucker rod pumps. Sucker rod pump equipment comprises a tube bottoming out in a dish with a standing valve. Within the tube is piston comprising a valve therein also known as a traveling valve. Ths piston is connected to a ground level prime mover by a longitudinal array of end-to-end connected sucker rods, i.e., a sucker rod string. The prime mover drives the piston up and down within the tube. On up-strokes of the piston oil passes through the standing valve into the tube and on downstrokes of the piston, oil passes through the piston valve to the topside of the piston to become part of the column of oil on the piston raised on every up-stroke to dump a top of the column into collection equipment.
Sucker rod pump equipment is widely used despite recognition of undesirably high noise, cost, weight, driving energy requirements and vulnerability to breakage. The massive above ground equipment associated therewith is also esthetically undesirable. In very deep wells the sucker rod string is tapered or straight, the sucker rod diameter occupies a high proportion of tube diameter thereby creating high friction losses and wear and limiting throughput for given tube diameter and stroke length, both of which are limited as a practical matter.
It is an important object of the invention to overcome one or more of the above drawbacks.
It is a further object of the present invention to provide an improvement in pumping in oil wells and other applications which avoids the above-ground motor and mechanical transmission and their associated cost and noise, friction and mechanical breakdown vulnerabilities, consistent with the preceding object.
It is a further object of the invention to increase stroke length consistent with one or more of the preceding objects.
It is a further object of the invention to reduce cost consistent with one or more of the preceding objects.
It is a further object of the invention to increase piston diameter consistent with one or more of the preceding objects.
It is a further object of the invention to reduce wear consistent with one or more of the preceding objects.
It is a further object of the invention to reduce the vulnerability to breakage of the line within the well consistent with one or more of the preceding objects.
It is a further object of the invention to provide a long life, reliable pumping apparatus consistent with one or more of the preceding objects.
It is a further object of the invention to provide precise control of stroke consistent with one or more of the preceding objects.